BACKGROUND: An association between obesity and asthma has been reported. The prevalence of airway hyperresponsiveness (AHR), results of skin prick tests, body mass index (BMI), and asthma symptoms were examined in schoolchildren. METHODS: The results of BMI (kg/m2) determination, skin prick testing, spirometry, asthma questionnaires, and methacholine challenge tests were obtained in a cross-sectional survey of 667 schoolchildren. The methacholine concentration causing a 20% fall in FEV1 (PC20) was used as the threshold of AHR. If the PC20 was less than 16 mg/mL, the subject was considered to have methachloine mediated AHR. RESULTS: The mean BMI was 17.1+/-0.09 kg/m2. The prevalence of AHR was 42.7%. The sensitization rate to common inhalant allergens was 30.3%. PC20 in children with BMIs >or=17.1 kg/m2 was significantly lower than that in children with BMIs 17.1 kg/m2. The mean BMIs of boys and girls were not significantly different. The levels of PC20 by sex were not different. The children were grouped by sex into percentile of BMI. PC20 in boys was lower in the obese group than in the non-weight and overweight groups (p<0.05). PC20 in boys and girls with atopy was significantly lower than in those without atopy. In a multiple logistic regression model that included all of the children and adjusted for confounding variables, independent associations with AHR were seen with BMI, asthma symptoms, and atopy . CONCLUSIONS: BMI had an association with AHR in school-age boys.
Sex Factors ; *Schools ; Risk Factors ; Questionnaires ; Obesity/*physiopathology ; Methacholine Chloride/*pharmacology ; Male ; Korea/epidemiology ; Hypersensitivity, Immediate/epidemiology/physiopathology ; Humans ; Health Surveys ; Female ; Comorbidity ; Child ; Bronchial Hyperreactivity/epidemiology/*physiopathology ; Body Mass Index ; Asthma/*physiopathology ; Age Factors

Passive smoking is a major cause of respiratory morbidity, and is associated with increased bronchial responsiveness in children. To evaluate the effect of smoking by a parent on asthma symptoms, atopy, and airway hyperresponsiveness (AHR), we conducted a cross-sectional survey of 503 schoolchildren that involved questionnaires, spirometry, allergy testing, and a bronchial challenge test. If the PC20 methacholine was less than 16 mg/mL, the subject was considered to have AHR. The prevalence of a parent who smoked was 68.7%. The prevalence of AHR was 45.0%. The sensitization rate to common inhalant allergens was 32.6%. Nasal symptoms such as rhinorrhea, sneezing, nasal itching, and nasal obstruction were present in 42.7%. Asthma symptoms such as cough and wheezing were present in 55.4%. The asthma symptoms were significantly more prevalent in children who had a parent who smoked than in those whose parents did not. The nasal symptoms, atopy, and AHR did not differ according to whether a parent smoked. In a multiple logistic regression model, the asthma symptoms and atopy were independently associated with AHR, when adjusted for confounding variables. Passive smoking contributed to asthma symptoms in schoolchildren and was not an independent risk factor of airway hyperresponsiveness in an epidemiological survey.
Adult ; Asthma/*epidemiology/physiopathology ; Bronchial Hyperreactivity/*epidemiology/physiopathology ; Child ; Data Collection ; Female ; Human ; Hypersensitivity/*epidemiology/physiopathology ; Male ; Parents ; Prevalence ; Risk Factors ; Support, Non-U.S. Gov't ; Tobacco Smoke Pollution/*adverse effects/*statistics & numerical data

BACKGROUND/AIMS: We sought to increase our understanding of the rhinitis-asthma relationship and improve strategies for the treatment of patients with these diseases. The aim of this study was to identify a connection between upper airway inflammation and lower airway responsiveness. METHODS: We counted eosinophils on nasal smears, and performed spirometry, allergic skin tests, and methacholine challenge tests in 308 schoolchildren plus a questionnaire on respiratory symptoms. The methacholine concentration causing a 20% fall in forced expiratory volume in 1 second (PC20 < 25 mg/mL) was used as the threshold of bronchial hyperresponsiveness (BHR). RESULTS: In total, 26% of subjects had positive nasal eosinophils on a smear, and 46.2% of subjects had BHR at < 25 mg/mL methacholine PC20. Nasal symptoms were higher in subjects with than without nasal eosinophils (p = 0.012). Asthma symptoms did not differ between subjects with and without nasal eosinophils. Nasal eosinophils were higher in subjects with atopy than those without (p = 0.006), and there was no difference in PC20 methacholine according to atopy (15.5 +/- 1.07 vs. 17.5 +/- 0.62; p > 0.05). No difference in BHR was detected when comparing subjects with and without nasal eosinophils. There were significant differences in the PC20 between subjects with greater than 50% nasal eosinophils and without nasal eosinophils (11.01 +/- 2.92 mg/mL vs. 17.38 +/- 0.61 mg/mL; p < 0.001). CONCLUSIONS: These findings demonstrated that nasal eosinophilic inflammation might contribute to lower airway responsiveness in schoolchildren, based on an epidemiological survey.
Adolescent ; Age Distribution ; Age Factors ; Asthma/diagnosis/*epidemiology/physiopathology ; Bronchial Hyperreactivity/diagnosis/*enzymology/physiopathology ; Bronchial Provocation Tests ; Child ; Eosinophilia/diagnosis/*epidemiology/immunology ; Eosinophils/immunology ; Female ; Health Surveys ; Humans ; Intradermal Tests ; Leukocyte Count ; Lung/*physiopathology ; Male ; Nasal Mucosa/*immunology ; Republic of Korea/epidemiology ; Rhinitis/diagnosis/*epidemiology/immunology ; Spirometry ; Surveys and Questionnaires